1. Field of the Invention
The present invention relates to a liquid jet head equipped with a piezoelectric element consisting of a lower electrode, a piezoelectric layer, and an upper electrode as well as a piezoelectric element.
2. Description of Related Arts
A piezoelectric element used in a liquid jet head or the like is an element composed of a piezoelectric film made of a piezoelectric material having an electromechanical conversion function sandwiched between two electrodes. The piezoelectric film is composed of, for example, crystallized piezoelectric ceramics.
Liquid jet heads having such a piezoelectric element include, for example, an ink jet recording head in which a portion of a pressure-generating chamber linked to a nozzle opening for discharging ink droplets is composed of a diaphragm, wherein the diaphragm is deformed by the piezoelectric element, thereby pressurizing ink contained in the pressure-generating chamber so that ink droplets can be discharged from the nozzle opening. Two kinds of ink jet recording heads have been put to practical use: ones based on a longitudinal-vibration-mode actuator that extends/retracts along the axial direction of a piezoelectric element and ones based on a flexural-mode actuator. For high density arrangement, such an actuator needs a piezoelectric element that offers a great strain even with a low driving voltage, in other words, a piezoelectric element that generates a marked displacement.
Also, ones having a piezoelectric layer whose X-ray diffraction peak position is specified in order that the displacement property of the piezoelectric layer is improved are proposed in, for example, Japanese Unexamined Patent Application Publication No. 2006-278835.
However, even when such a highly dielectric film was used to form a piezoelectric element, the obtained piezoelectric properties were unsatisfactory. Note that this problem is not limited to ink jet recording heads and other liquid jet heads and is noted also in other actuator apparatuses.